An Organic Light-Emitting Diode (OLED) display is one of focuses in the field of researches on the existing flat panel displays, and the OLED display has advantages of low power consumption, a low product cost, self-luminescence, a wide angle of view, a high response speed, etc., over a liquid crystal display; and at present, the OLED display has come to take the place of the traditional Liquid Crystal Display (LCD) in the field of flat panel displays including mobile phones, PDAs, digital photos, etc., where the design of a pixel circuit is a core technology in the OLED display, and researches on its design are of great significance.